Pass FormatContext to NeedsParentheses

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## Summary

I started working on this because I assumed that I would need access to options inside of `NeedsParantheses` but it then turned out that I won't. 
Anyway, it kind of felt nice to pass fewer arguments. So I'm gonna put this out here to get your feedback if you prefer this over passing individual fiels. 

Oh, I sneeked in another change. I renamed `context.contents` to `source`. `contents` is too generic and doesn't tell you anything. 

<!-- What's the purpose of the change? What does it do, and why? -->

## Test Plan

It compiles

crates/ruff_python_formatter/src/expression/parentheses.rs

@@ -1,4 +1,3 @@
-use crate::comments::Comments;
 use crate::context::NodeLevel;
 use crate::prelude::*;
 use crate::trivia::{first_non_trivia_token, first_non_trivia_token_rev, Token, TokenKind};
@@ -11,16 +10,14 @@ pub(crate) trait NeedsParentheses {
     fn needs_parentheses(
         &self,
         parenthesize: Parenthesize,
-        source: &str,
-        comments: &Comments,
+        context: &PyFormatContext,
     ) -> Parentheses;
 }
 
 pub(super) fn default_expression_needs_parentheses(
     node: AnyNodeRef,
     parenthesize: Parenthesize,
-    source: &str,
-    comments: &Comments,
+    context: &PyFormatContext,
 ) -> Parentheses {
     debug_assert!(
         node.is_expression(),
@@ -34,13 +31,13 @@ pub(super) fn default_expression_needs_parentheses(
         Parentheses::Never
     }
     // `Optional` or `Preserve` and expression has parentheses in source code.
-    else if !parenthesize.is_if_breaks() && is_expression_parenthesized(node, source) {
+    else if !parenthesize.is_if_breaks() && is_expression_parenthesized(node, context.source()) {
         Parentheses::Always
     }
     // `Optional` or `IfBreaks`: Add parentheses if the expression doesn't fit on a line but enforce
     // parentheses if the expression has leading comments
     else if !parenthesize.is_preserve() {
-        if comments.has_leading_comments(node) {
+        if context.comments().has_leading_comments(node) {
             Parentheses::Always
         } else {
             Parentheses::Optional